Molds are normally found in the environment and are part of the natural cycle of decay. However, excess moisture in a building can cause mold to grow indoors. Controlling moisture, by fixing leaks, having adequate ventilation, and cleaning up after floods or other water damage is the key to preventing mold growth.

Health effects from mold depend on an individual's:

• General Health
• Amount of exposure
• Degree of sensitivity to molds

Some people are allergic to molds, and molds can triggers asthma episodes. Allergic rhinitis, which can mimic the common cold, is another condition that can be caused by exposure to mold. Many of the other health claims made about mold, e.g. memory loss, are not supported by research.

Some molds can produce toxins under certain circumstances, but this does not occur everywhere there is mold growth. Research on the presence, detection and effects of mold toxins is ongoing and at this time there are many unanswered questions. One mold in particular, Stachybotrys atra (chartarum) has received a lot of attention. The initial reports on the health affects of this mold have been revised by the Centers for Disease Control and Prevention. Fear of mold has been sensationalized in the news media and on many websites, and citizens need to be cautious when considering expensive testing and be informed about the kind of information that the testing will yield. As a rule, mold tesing in private homes when visible mold growth is present is not recommended by the Centers of Disease Control and Prevention nor the US Environmental Protection Agency.